Americas and Oceania Group - International Plant Nutrition Institute

Site-Specific Nutrient Management in Maize Growing Districts of Tamil Nadu
Project Leader: S. Jeyaraman, Tamil Nadu Agricultural University, Directorate of Crop Management, Coimbatore,
Tamil Nadu. E-mail: directorscms@tnau.ac.in, sjtnau@gmail.com
Project Cooperators: A. Velayutham, Central Farm Unit, TNAU Coimbatore, N. Sakthivel, Central Farm Unit, TNAU
Coimbatore, P. Janaki, Central Farm Unit, TNAU Coimbatore, R. Ravi Kesavan, Maize Research Station, TNAU,
Ga. Dheebakaran, Maize Research Station, C. Bharathi, Maize Research Station, R. Kavimani, Cotton Research
Station, T. Sherene, R. Baskar, B. Chandrasekaran, SWMRI, S. Vallalkannan, and S. Suganya.
Maize is becoming an important crop in Tamil Nadu, currently being cultivated in 244,200 ha area with a
production of 1.1 M t. However, the current productivity levels of maize average only about 4.7 t/ha when
compared to it’s yield potential of more than 10 t/ha. Inadequate and improper fertilization, sub-optimal
official state recommendations, and lack of focus on the use of secondary- and micro-nutrients are some of
the key factors responsible for low maize yields. Moreover, application of fertilizers varies from field-tofield,
and looking at the extent of variation in soil fertility across the farmer fields, single homogenous state
recommendation may not be very helpful in improving maize yields. Conservation tillage systems pose
greater challenges for farmers due to lack of information on efficient nutrient management strategies under
these systems. The current project goal was to develop site-specific fertilizer recommendations using Nutrient
Expert decision support tool in four major maize growing districts of Tamil Nadu. For this, 16 locations
representing variable maize growing environments were selected in Perambalur, Thanjavur, Vagarai, and
Coimbatore districts of Tamil Nadu, and a set of two experiments under conventional and conservational
tillage systems were conducted at four locations in each district. The first experiment compared Nutrient
Expert-based fertilizer recommendation with state recommendation and farmer practice, while the second
experiment looked at the yield response with ample NPK (250-100-120 kg N-P 2 O 5 -K 2 O/ha) along with
nutrient omission treatments for N, P, and K, respectively. The experimental soils were alkaline in reaction
(pH 8.1 to 8.3), low to medium in organic C (0.41 to 0.90%), low to medium in available N (176 to 252 kg/
ha), and medium to high in both available P (11 to 35 kg/ha) and available K (270 to 640 kg/ha).
Results obtained so far from two locations indicated no significant difference in grain and stover yields
of maize among the different crop establishment systems. Highest grain yield (8.6 t/ha) was obtained with
Nutrient Expert-based recommendation followed by state recommendation (8.1 t/ha) and farmer practice (6.9
t/ha). Yields due to ample NPK and omission of N, P, and K were 7.48, 7.08, 7.16, and 7.13 t/ha, respectively.
The project is expected to continue until mid-2013. India-018
Site-Specific Nutrient Management (SSNM) for Maximum Economic Yield and Quality of Transgenic Cotton in Northern
Karnataka
Project Leader: D. P. Biradar, University of Agricultural Sciences Agronomy Professor (Agronomy) & Editor
Publication Centre, Karnataka Dharwar, Karnataka. E-mail: dpbiradar@yahoo.com
Project Cooperators: Y. R. Aladakatti, Senior Scientist, Agronomy (yraladakatti@rediffmail.com) and M. A.
Basavanneppa, Assistant Agronomist (Cotton) Agricultural Research Station, Siruguppa.
Northern Karnataka has currently 70% of the total cotton area under transgenic (Bt) cotton in India.
However, low average productivity and limited information on nutrient management in Bt cotton led to this
study evaluating the effect of site-specific nutrient management (SSNM) on transgenic cotton.
On-station experiments conducted at Dharwad and Sirugappa for 3 years revealed that planting geometry of
90 x 60 cm at Dharwad and 90 x 30 cm at Sirugappa resulted in higher seed cotton yield of 2,945 and 2,335
kg/ha, respectively. Similarly, nutrient application for a yield target of 4,000 kg/ha resulted in a seed cotton
yield of 3.5 and 2.4 t/ha at Dharwad and Siruguppa, respectively. Higher net returns of INR 75,029/ha and
benefit-to-cost (B:C) ratio of 4.06 were observed at Dharwad as opposed to only INR 45,077/ha and B:C ratio
of 3.03 at Siruguppa. This indicated that target yields were attained only under Dharwad conditions.
Results from Dharwad were tested and confirmed in the farmer fields at 15 locations representing soil types
varying from medium-to-deep black and red soils. SSNM recommendations for yield targets of 3,000 kg/
ha (160:75:100 N:P 2 O 5 :K 2 O kg/ha + 25 kg ZnSO 4 ) and 4,000 kg/ha (220:100:160 N:P 2 O 5 :K 2 O kg/ha + 25
kg ZnSO 4 ) were compared with state recommendation (100:50:50 N:P 2 O 5 :K 2 O kg/ha) and farmer practice
(average of 124:72:56 N:P 2 O 5 :K 2 O kg/ha). Nutrient application for a yield target of 3,000 kg/ha resulted in
average cotton yields of 2,900 (range 2,500 to 3,180) kg/ha. Nutrient application for 4,000 kg/ha resulted in
an average seed cotton yield of 3,340 kg/ha across the farmer fields with yield targets not attained at majority
of locations. Using state fertilizer recommendations, cotton yields varied from 2,000 to 2,750 kg/ha, and with
farmer practice, they varied between 1,900 and 2,950 kg/ha, respectively. Thus, SSNM recommendations
for 3,000 kg/ha resulted in a yield increase of 19% over farmer practice (2,440 kg/ha) and 20% over state
recommendation (2,420 kg/ha). The results were shown to farmers through organized field days and have also
been incorporated in the cotton video currently in production. The results will also be presented in the state
review meeting during October 2012 for revising state fertilizer recommendation for Bt cotton. India-010
IPNI Interpretive Summaries 95